Photo release: Ants in space?
- Tantalising detail in ant-shaped nebula illuminates last moments of
Sun-like stars
1-Feb-2001 Observed from ground-based telescopes, the so-called ‘ant
nebula’ (Menzel 3, or Mz3) resembles the head and thorax of a common
garden ant. This dramatic NASA/ESA Hubble Space Telescope image,
showing 10 times more detail, reveals the ‘ant’s body’ as a pair of
fiery lobes protruding from a dying, Sun-like star.
Hubble images directly challenge old ideas about planetary nebulae -
the last stage in the life of Sun-like stars. This striking image has
been assembled by the Hubble Heritage project and ESA from earlier
images stored in the Hubble Archive. It is one of a series of images
of planetary nebulae that have shown that our Sun’s fate will
probably be more interesting, complex and striking than astronomers
imagined even just a few years ago.
In particular, the image of Mz3 reveals intriguing symmetrical
patterns in the turbulent ejection of gas from the dying star at the
centre of Mz3, unlike the chaotic patterns expected from an ordinary
explosion. Scientists using Hubble try to understand how a spherical
star can produce such prominent, non-spherical symmetries in the gas
that it ejects.
One possibility is that the central star of Mz3 has a closely
orbiting companion that exerts strong gravitational tidal forces,
which shape the outflowing gas. This model demands that the orbiting
companion star be close to the dying star, at about the distance of
the Earth from the Sun. At this distance, the orbiting companion star
must be very close to the hugely bloated hulk of the dying star, or
may even be orbiting inside it - a strange existence, not unlike that
of the duck swallowed by the wolf in the old tale of “Peter and the
Wolf”.
A second possibility is that as the dying star spins, its strong
magnetic fields are twirled into complex shapes like strands of
spaghetti. The glowing gases in the nebula are forced to trace out
these complex patterns, allowing astronomers to ‘see’ the usually
invisible magnetic field. Winds of charged particles moving at speeds
up to 3.5 million km/hour away from the star – much like those in our
local ‘solar wind’, but millions of times denser – are able to follow
the twisted magnetic field on their way out into space. These dense
winds can be rendered visible by ultraviolet light from the hot
central star or from collisions with the ambient gas that excites the
material into florescence.
No other planetary nebula observed by Hubble closely resembles Mz3.
M2-9 is perhaps the most similar, but the outflow speeds in Mz3 are
up to 10 times larger than those of M2-9. Interestingly, the very
massive, young star, Eta Carinae, shows a very similar outflow
pattern to that of Mz3.
Astronomers Bruce Balick (University of Washington, USA) and Vincent
Icke (Leiden University, The Netherlands) used Hubble to observe this
planetary nebula, Mz3, with the Wide Field Planetary Camera 2 in July
1997. A year later, astronomers Raghvendra Sahai and John Trauger of
the Jet Propulsion Lab in California snapped pictures of Mz3 using
slightly different filters. The intriguing image shown here is a
composite of three filters from these two datasets.
Image credit: NASA, ESA and the Hubble Heritage Team (STScI/AURA)
Notes for editors:
The Hubble Space Telescope is a project of international
co-operation between ESA and NASA.
This photo release is issued jointly by ESA and NASA.
Acknowledgement: Bruce Balick (University of Washington, USA),
Vincent Icke (Leiden University, The Netherlands), R. Sahai and John
Trauger (Jet Propulsion Lab, USA).
Contacts:
Lars Lindberg Christensen
Hubble European Space Agency Information Centre, Garching, Germany
Phone: +49-(0)89-3200-6306
Cellular (24 hr): +49-(0)173-38-72-621
E-mail: lars@eso.org
Raghvendra Sahai
Jet Propulsion Lab, Pasadena, USA
Phone: +1-818-354-0452
E-mail: sahai@bb8.jpl.nasa.gov
Bruce Balick
University of Washington, Seattle, USA
Phone: +1-206-543-7683
E-mail: balick@astro.washington.edu
Vincent Icke
Leiden University, Leiden, The Netherlands
Phone: +31-71-527-58-43
E-mail: icke@strw.LeidenUniv.nl
Howard Bond, Space Telescope Science Institute, Baltimore, USA
Phone: +1-410-338-4718
E-mail: bond@stsci.edu